The present invention relates generally to hinge fittings for a reclining vehicle seat structure and, more particularly, to a novel design and arrangement of the lock actuating mechanism for such a seat structure.
Vehicle seats are generally designed for simultaneous forward and rearward adjustment of the seat and seatback members. Other adjustments (e.g., vertical or tilt) of both seat and seatback members, as a unit, may or may not be provided. However, it is often desirable to allow for adjustment of the seatback member, relative to the seat member, to provide an adjustable reclining seatback. Hinge fittings which provide for this type of adjustment normally include a fixed support bracket mounted to the vehicle seat, a seatback support member which is adjustable through a range of reclining positions and which is attached to the seatback and pivotally connected to all of the following: the fixed support bracket, a locking member to lock the seatback support at various inclined positions, and a lock actuating mechanism for engaging or disengaging the locking member.
Examples of hinge fittings of this general type are shown in U.S. Pat. No. 3,999,247 to Cremer and U.S. Pat. No. 3,973,288 to Pickles. Refinements related to the specific shape and dimensional characteristics of the lock actuating mechanism, which in this patent includes a cam and a pawl, are shown in U.S. Pat. No. 4,223,947, also to Cremer, and U.S. Pat. No. 4,875,735 to Moyer and the Applicant. Other refinements have been made to the pivot arm assembly and linkage which controls the lock actuating mechanism, like those found in U.S. Pat. No. 4,875,735 to Moyer and the Applicant and U.S. Pat. No. 4,872,726 to White.
Problems with hinge fittings of the above-referenced types relate to undesired contact between the linkage of the pivot arm assembly and other components in the hinge fitting. This occurs during adjustment of the level of reclination which naturally requires movement of the hinge fitting mechanisms. Also, undesired contact can occur between the linkage and both the seat to which the hinge fitting is attached, as well as the user. Specifically, placement of the linkage connecting rod and the corresponding biasing spring, collectively the linkage assembly, in previously designed hinge fittings left portions of the linkage assembly, and in particular the biasing spring, exposed to external surroundings. During adjustment of the seat, when the user's hand is near the linkage assembly, movement of the linkage assembly sometimes caused damage to the seat itself and posed a threat of injury to the user.
Another problem with prior art hinge fittings was the difficulty of assuring that the assembled fitting would withstand sufficient torque when in the locked position without releasing. This problem is accentuated by the stacking of tolerances effect that occurs when assembling the fitting. Although one previous prior fitting determines whether the stacked tolerances were within the acceptable range by whether an alignment dot appeared in the upper or lower half of a view window defined by a sandwich plate, this approach has significant limitations.
Also, hinge fittings are used in commercial applications where a certain maximum reclining position is desired. Specifically, most applications utilize hinges having a maximum angle of reclination of 30.degree. or 45.degree.. Accordingly, manufacturers currently manufacture and warehouse hinges having a maximum angle of reclination of 30.degree. and hinges having a maximum angle of reclination of 45.degree..